Over the years, neuropathologic characterization of autopsy-derived brain tissues has been the cornerstone of research on Guam amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC). Within this Core we will provide these services while also serving to provide properly preserved and characterized brain samples to researchers within the Program. Specifically, the Neuropathology-Brain Bank Core will provide supervision and expertise to the Clinical Core to enable the Program to properly obtain autopsy-derived brain specimens with a minimum of post-mortem delay from individuals suffering from ALS/PDC and from Guam residents without a diagnosis of neurodegenerative disorders. The brain specimens obtained by the Clinical Core will be partially dissected on Guam (with half of the brain fixed and half frozen) and sent to the Core for further dissection and characterization. Upon receipt at the Core, each specimen will undergo full neuropathologic evaluation. Besides rendering a neuropathologic diagnosis, the extent and distribution or relevant neuropathologic lesions will be documented and entered into the neuropathology data base. Both frozen and fixed portions of the specimens will be provided to Program researchers. Remaining portions of the brain samples will be preserved in a Brain Bank and serve as a national/international resource for qualified researchers interested in working on the unique and important material.